983
FNCA52 TJSJ 201930
FWFSJU
FIRE WEATHER PLANNING FORECAST FOR PUERTO RICO
NATIONAL WEATHER SERVICE SAN JUAN PR
330 PM AST THU AUG 20 2026
DISCUSSION
SURFACE WEATHER STATIONS HAVE BEEN RECORDING MINIMUM RELATIVE
HUMIDITY VALUES IN THE MID 50S AND EASTERLY WINDS NEAR 15 MPH,
WITH GUSTS UP TO 25 TO 28 MPH, PARTICULARLY ACROSS THE SOUTHERN
PLAINS AND HILLS OF PUERTO RICO AND ST. CROIX. AN ELEVATED FIRE
DANGER THREAT PREVAILS IN THESE AREAS DUE TO A COMBINATION OF DRY
ATMOSPHERIC CONDITIONS, ONGOING RAINFALL DEFICITS, STRESSED
VEGETATION, AND DRY FUELS. CONDITIONS WILL REMAIN FAVORABLE FOR
RAPID FIRE IGNITION AND SPREAD. THEREFORE, A FIRE DANGER
STATEMENT (RFD) REMAINS IN EFFECT UNTIL 5 PM AST THIS AFTERNOON,
PARTICULARLY ACROSS THE SOUTHERN PLAINS AND HILLS OF PUERTO RICO.
CONTINUE TO MONITOR THE FORECAST, AS ADDITIONAL FIRE WEATHER
PRODUCTS MAY BE NEEDED IN THE COMING DAYS.
PRZ014-210800-
SOUTHEAST COASTAL PLAINS-
330 PM AST THU AUG 20 2026
TONIGHT FRI FRI NIGHT SAT
CLOUD COVER MCLEAR MCLEAR MCLEAR MCLEAR
PRECIP TYPE NONE SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 0 10 10 20
TEMP (24H TREND) 75 (-3) 92 (+1) 75 93
RH % (24H TREND) 82 (-6) 45 (-7) 85 47
WIND 20FT/EARLY(MPH) E 17 E 17 NE 14 E 14
WIND 20FT/LATE(MPH) NE 13 E 19 NE 10 E 17
MIXING HGT(FT-AGL/MSL) 5250 5520
TRANSPORT WND (MPH) E 18 E 16
VENT RATE (KT-FT) 84000 77280
DISPERSION 5 5
DSI 4 6 3 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ015-210800-
SOUTHERN HILLS-
330 PM AST THU AUG 20 2026
TONIGHT FRI FRI NIGHT SAT
CLOUD COVER MCLEAR MCLEAR MCLEAR MCLEAR
PRECIP TYPE SHOWERS SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 0 20 10 20
TEMP (24H TREND) 71 (-4) 90 (+3) 71 90
RH % (24H TREND) 94 (0) 52 (-8) 96 55
WIND 20FT/EARLY(MPH) E 14 E 13 NE 13 E 11
WIND 20FT/LATE(MPH) E 13 E 14 NE 12 E 12
MIXING HGT(FT-AGL/MSL) 5730 5890
TRANSPORT WND (MPH) E 17 E 14
VENT RATE (KT-FT) 85950 70680
DISPERSION 5 5
DSI 4 6 3 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ016-210800-
NORTH COASTAL PLAINS-
330 PM AST THU AUG 20 2026
TONIGHT FRI FRI NIGHT SAT
CLOUD COVER MCLEAR MCLEAR PCLDY MCLEAR
PRECIP TYPE SHOWERS SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 10 20 20 20
TEMP (24H TREND) 74 (-3) 90 (0) 75 91
RH % (24H TREND) 95 (-1) 60 (-3) 97 59
WIND 20FT/EARLY(MPH) E 21 E 17 E 18 E 12
WIND 20FT/LATE(MPH) E 12 E 21 E 13 E 19
MIXING HGT(FT-AGL/MSL) 4890 5270
TRANSPORT WND (MPH) E 20 E 15
VENT RATE (KT-FT) 83130 68510
DISPERSION 5 5
DSI 5 6 5 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ017-210800-
NORTHERN HILLS-
330 PM AST THU AUG 20 2026
TONIGHT FRI FRI NIGHT SAT
CLOUD COVER MCLEAR MCLEAR MCLEAR MCLEAR
PRECIP TYPE NONE SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 0 30 10 40
TEMP (24H TREND) 72 (-2) 89 (0) 72 90
RH % (24H TREND) 96 (-3) 61 (-2) 99 62
WIND 20FT/EARLY(MPH) E 19 E 16 E 17 E 10
WIND 20FT/LATE(MPH) E 10 NE 19 E 11 NE 16
MIXING HGT(FT-AGL/MSL) 5660 5590
TRANSPORT WND (MPH) E 16 E 13
VENT RATE (KT-FT) 79240 61490
DISPERSION 5 5
DSI 4 6 4 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ018-210800-
WEST COAST-
330 PM AST THU AUG 20 2026
TONIGHT FRI FRI NIGHT SAT
CLOUD COVER MCLEAR MCLEAR MCLEAR MCLEAR
PRECIP TYPE SHOWERS TSTMS NONE SHOWERS
CHANCE PRECIP (%) 20 50 0 40
TEMP (24H TREND) 72 (-3) 92 (0) 73 94
RH % (24H TREND) 96 (-1) 57 (-5) 97 56
WIND 20FT/EARLY(MPH) E 16 E 13 E 18 E 12
WIND 20FT/LATE(MPH) E 11 SE 14 E 16 E 12
MIXING HGT(FT-AGL/MSL) 4910 4660
TRANSPORT WND (MPH) E 9 SE 9
VENT RATE (KT-FT) 39280 37280
DISPERSION 5 5
DSI 4 6 3 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ019-210800-
EASTERN INTERIOR-
330 PM AST THU AUG 20 2026
TONIGHT FRI FRI NIGHT SAT
CLOUD COVER MCLEAR MCLEAR PCLDY MCLEAR
PRECIP TYPE SHOWERS SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 10 30 30 40
TEMP (24H TREND) 73 (-4) 90 (+2) 73 90
RH % (24H TREND) 94 (0) 58 (-3) 96 57
WIND 20FT/EARLY(MPH) E 14 E 13 E 13 E 12
WIND 20FT/LATE(MPH) E 13 E 13 E 13 E 12
MIXING HGT(FT-AGL/MSL) 5890 6610
TRANSPORT WND (MPH) E 17 E 15
VENT RATE (KT-FT) 88350 85930
DISPERSION 5 5
DSI 4 6 3 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ022-210800-
LUQUILLO MOUNTAIN RANGE-
330 PM AST THU AUG 20 2026
TONIGHT FRI FRI NIGHT SAT
CLOUD COVER MCLEAR MCLEAR PCLDY PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 20 20 30 40
TEMP (24H TREND) 71 (-3) 85 (+3) 70 86
RH % (24H TREND) 98 (+2) 65 (-7) 99 65
WIND 20FT/EARLY(MPH) E 13 E 12 E 11 E 10
WIND 20FT/LATE(MPH) E 11 E 12 E 10 E 10
MIXING HGT(FT-AGL/MSL) 4920 4750
TRANSPORT WND (MPH) E 20 E 16
VENT RATE (KT-FT) 83640 66500
DISPERSION 5 5
DSI 6 6 4 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ023-210800-
CENTRAL MOUNTAIN RANGE-
330 PM AST THU AUG 20 2026
TONIGHT FRI FRI NIGHT SAT
CLOUD COVER MCLEAR MCLEAR MCLEAR MCLEAR
PRECIP TYPE NONE TSTMS SHOWERS SHOWERS
CHANCE PRECIP (%) 0 40 0 30
TEMP (24H TREND) 68 (-4) 88 (+3) 68 88
RH % (24H TREND) 98 (0) 60 (-4) 100 63
WIND 20FT/EARLY(MPH) E 11 E 10 NE 12 E 9
WIND 20FT/LATE(MPH) E 8 E 12 E 10 E 9
MIXING HGT(FT-AGL/MSL) 7460 6110
TRANSPORT WND (MPH) E 12 E 13
VENT RATE (KT-FT) 74600 67210
DISPERSION 5 5
DSI 2 6 2 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ024-210800-
CAYEY MOUNTAIN RANGE-
330 PM AST THU AUG 20 2026
TONIGHT FRI FRI NIGHT SAT
CLOUD COVER MCLEAR MCLEAR PCLDY MCLEAR
PRECIP TYPE SHOWERS SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 10 30 30 40
TEMP (24H TREND) 71 (-3) 86 (+2) 71 86
RH % (24H TREND) 97 (-1) 62 (-6) 100 63
WIND 20FT/EARLY(MPH) E 13 E 12 NE 11 E 10
WIND 20FT/LATE(MPH) E 11 E 12 NE 9 E 11
MIXING HGT(FT-AGL/MSL) 5110 5600
TRANSPORT WND (MPH) E 20 E 16
VENT RATE (KT-FT) 86870 78400
DISPERSION 5 5
DSI 5 6 3 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ025-210800-
VIEQUES-
330 PM AST THU AUG 20 2026
TONIGHT FRI FRI NIGHT SAT
CLOUD COVER MCLEAR MCLEAR PCLDY PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 10 20 30 30
TEMP (24H TREND) 80 (-1) 89 (0) 78 91
RH % (24H TREND) 82 (-5) 60 (-3) 86 58
WIND 20FT/EARLY(MPH) E 18 E 16 E 16 E 14
WIND 20FT/LATE(MPH) E 16 E 16 E 14 E 13
MIXING HGT(FT-AGL/MSL) 4120 3330
TRANSPORT WND (MPH) E 21 E 17
VENT RATE (KT-FT) 74160 49950
DISPERSION 5 5
DSI 6 6 6 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ026-210800-
CULEBRA-
330 PM AST THU AUG 20 2026
TONIGHT FRI FRI NIGHT SAT
CLOUD COVER MCLEAR MCLEAR PCLDY PCLDY
PRECIP TYPE SHOWERS SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 10 20 30 30
TEMP (24H TREND) 80 (-1) 90 (+2) 79 91
RH % (24H TREND) 85 (-4) 63 (-4) 90 61
WIND 20FT/EARLY(MPH) E 18 E 16 E 16 E 14
WIND 20FT/LATE(MPH) E 17 E 16 E 16 E 13
MIXING HGT(FT-AGL/MSL) 4110 3260
TRANSPORT WND (MPH) E 21 E 18
VENT RATE (KT-FT) 73980 52160
DISPERSION 5 5
DSI 6 6 6 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
PRZ027-210800-
SOUTHWEST COASTAL PLAINS AND MONA ISLAND-
330 PM AST THU AUG 20 2026
TONIGHT FRI FRI NIGHT SAT
CLOUD COVER MCLEAR MCLEAR MCLEAR MCLEAR
PRECIP TYPE NONE SHOWERS NONE SHOWERS
CHANCE PRECIP (%) 0 20 0 20
TEMP (24H TREND) 75 (-3) 91 (0) 74 94
RH % (24H TREND) 86 (-6) 50 (-6) 91 49
WIND 20FT/EARLY(MPH) E 21 E 19 E 13 E 17
WIND 20FT/LATE(MPH) E 17 SE 21 E 12 SE 17
MIXING HGT(FT-AGL/MSL) 5040 4980
TRANSPORT WND (MPH) E 18 E 17
VENT RATE (KT-FT) 80640 74700
DISPERSION 5 5
DSI 5 6 3 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
VIZ001-210800-
SAINT THOMAS AND SAINT JOHN-
330 PM AST THU AUG 20 2026
TONIGHT FRI FRI NIGHT SAT
CLOUD COVER CLEAR MCLEAR PCLDY PCLDY
PRECIP TYPE NONE SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 0 20 30 30
TEMP (24H TREND) 79 (-1) 88 (+1) 78 90
RH % (24H TREND) 86 (-2) 63 (-3) 90 61
WIND 20FT/EARLY(MPH) E 18 E 16 E 16 E 16
WIND 20FT/LATE(MPH) E 17 E 16 E 16 E 13
MIXING HGT(FT-AGL/MSL) 4030 3210
TRANSPORT WND (MPH) E 21 E 16
VENT RATE (KT-FT) 72540 44940
DISPERSION 5 5
DSI 6 6 6 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
VIZ002-210800-
ST CROIX-
330 PM AST THU AUG 20 2026
TONIGHT FRI FRI NIGHT SAT
CLOUD COVER MCLEAR MCLEAR MCLEAR MCLEAR
PRECIP TYPE SHOWERS SHOWERS SHOWERS SHOWERS
CHANCE PRECIP (%) 10 10 10 10
TEMP (24H TREND) 80 (-1) 88 (0) 78 90
RH % (24H TREND) 84 (-3) 64 (-2) 89 62
WIND 20FT/EARLY(MPH) E 17 E 16 E 16 E 14
WIND 20FT/LATE(MPH) E 17 E 16 E 16 E 13
MIXING HGT(FT-AGL/MSL) 5040 4890
TRANSPORT WND (MPH) E 21 E 16
VENT RATE (KT-FT) 90720 68460
DISPERSION 5 5
DSI 6 6 6 6
RH RECOVERY EXCELLENT EXCELLENT
REMARKS...NONE.
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